Hello

Wondering if anyone here has experienced this fault or could point me in the right direction: Sometimes when I unlock the car the front side lights and rear tail lamps come on, when I open the door the centre screen comes up with the Jaguar logo, but when I put my foot on the brake pedal the steering lock does not disengage and the dashboard does not come to life. At this point the car wont start and the only way to sort it out is to disconnect the battery for 30 mins or so.

I have replaced the battery and the remote batteries are new. This fault does not happen every time.

Any help or pointers gratefully received.

Matt

 

Try reversing your order of events to start the car:
1. When you get in, don’t touch the brakes
2. Press and hold the ‘Start’ button
3. While holding the ‘Start’ button, step on the brake pedal
Use this order all the time, see if the car starts every time.

 

difficult without codes. As it ‘does not come to life’, it would be i interesting to know if the occurs when the fob is placed in the fob cradle, inside the centre arm rest.

 

Well - is the battery new / or low ? I put mine on a battery maintainer if - to keep the battery all charged up. I suggest you do this even if you park it for only a few days.

 

Agreed. I add a 2a. Wait for all chimes to stop.

 

Thanks for your input.

I have tried starting the car as suggested and it makes no difference. There are no chimes and the dash does not light. It makes no difference if the key is placed in the cubby.

Any other thoughts?

Thanks

Matt

 

too little information provided. Perhaps the pressure in the brake lines is built up and you need to press the brake pedal harder?
I’m ruling out the switch as you state “its intermittent”.

 

Thanks for your input. I can push as hard as possible on the brake and it makes no difference.

the unusual thing is every time this happens the external lights come on

 

Not unusual at all. Please see the “Lighting” section of your Owner’s Manual. If you have “Autolamps” enabled, the lights will come on with the activation of the ignition system.

I for one do not use these automatic settings as I have control issues, lol.

Now back to the point: Car intermittently, won’t engage the starter.
To help decipher the root cause, I propose turning off all automatic settings before taking on the procedure stated earlier in this thread.
So, to be clear;

1. ensuring all electrical systems are turned off
2. and without foot on brake
3. press and release start button, to activate the ignition system
4. wait for all electrical startup sounds to subside, allowing all modules to activate (and lessons leaned with other cars I’ve owned, pressurizing the fuel system)
5. press and hold brake foot pedal
6. press and release start button
7. engine should start
8. release brake foot pedal.

 

I think the interesting point here is the ‘no chimes’ part when you press the ‘start’ button.
Makes me think the button itself is the problem.
Might require cleaning or replacement.

 

If the autolamps feature is engaging, then the ignition system is engaged. So switch is working.
Still, without codes this is hunting in the dark. Too many variables still;
1. not enough current?
2. brake peddle switch
3. starter
4. ??

Take a look at the starting system diagram. We haven’t ruled out any component yet.

 

Let’s go back to the basic mantra: “battery,battery,battery…”. The fact that the battery is recent or new does not in any way guarantee that it is supplying sufficient power. The existing battery should be put on a proper charger to bring it to full voltage. As a point of reference, in the XK the undemanded illumination of exterior lamps is one of the signs of a battery in death throes. It seems counter-intuitive but it is true.

 

Hi, I have the same problem and i think it ultimately is a cluster issue as everything seems to be routed to it, but it's a nightmare to change. If I unlock the car with the smart key standing right next to the door all will be fine, the ignition comes on and the car will start. If I open the car from the other end of the drive the car will open fine but I have no ignition and the battery will need to be disconnected for a while. This does this every time, whether there is some signal from the smart key the cluster isn't seeing from a distance which opens the ignition circuit i just don't know but it is irritating. I purchased a new smart key (I needed a spare anyway) and it does the same with that key.

 

Sorry forgot to finish the post. You always know when it's going to fail as the sidelights come on as you open the driver door and there is nothing you can do other than disconnect the battery. I noticed if you dont have the key in the car when you reconnect the battery it still faults out as the car is searching for the ignition signal when the power comes on. If you do a search there are a few posts with this issue mentioned. Most of them had new Instrument Clusters fitted or repairs done to the cluster. Whilst I've got SDD I'm not brave enough to have a go as part of the cluster configuration is to delete the existing keys.
Cheers Ian

 

Spitjag

Thank you very much for your assistance, your fault is identical to mine so I will investigate having a new cluster fitted or the existing one repaired.
All the best

Matt

 

That's a big leap and I suggest backing up a bit.
1st, what year is your car? I've never owned an XK8 but to be sure you're in the right forum, XK8 is the X100 and this is the X150 forum, 2006 onward or here in the US, 2007 onward.
2nd, what is the resting voltage of your battery at the terminals? To measure this, use a voltmeter and check it in the morning before attempting start up (should be no issue there.) The voltage is very important to know and a lot of guys respond to that with "my battery is new" or "the battery s good" without actually sharing the voltage. So heed @gctippett and @sov211 comments here please.
3rd,consider investing in an OBD II code reader. There are some out there that connect to your phone and will read all Jag codes (Body, Chassis) and not just engine. The Autel AP200 will meet you needs.

Tackling an Instrument Cluster swap is risky imo. Without knowing the fault codes, you're guessing on a very expensive repair so this is where you want to address @guy comment. The codes will help us help you.

 

:-) @Sean W
Should we start BOLDING and CAPITALIZING your "2ND"? Its the easiest thing to do and yet it is always avoided.
And you missed one... The responses I like are the ones where "13"+ volts are referenced. Not possible for an at rest, 12v wet cell battery.

Cheers!

 

Whilst it is true that many of the faults of spurious messages and rough running can be attributed to a poorly charged or failing battery but when the manifested issue is exactly the same as a problem experienced by another owner who has gone through the rigours of replacing the battery, spending hours checking earth cables and harnesses as well as spending hundreds or pounds on SDD software to diagnose the problem then sometimes a more complex issue is the fault. The clue to the problem is the sidelights coming on when the driver door is opened, (one can assume the sidelights are not turned on at the switch) it is impossible to turn the sidelights off and only the disconnection of the battery will reset the car. If you look at some of the faults that can be apparent with the instrument cluster via SDD this phenomenon is described though it is usually attributed to an unsuccessful attempt to recode the existing cluster or a replacement. A search of the fault via the many jaguar forums mentions this issue though it is quite rare and a replacement or repaired instrument cluster has solved the problem.

 

Too true @Spitjag . And as I’m sure you aware aware, should the pinpoint tests be followed from the Workshop Manual, the root cause of “issues” can be efficiently sorted. Unfortunately, some choose to ignore these learned procedures then go on a replace this and that rampage.
One of the simplest tests in the workshop manual is the battery load test. As are the “car won’t start” set of tests.

 

I’m pleased to report that the fault has been found and rectified.

As suspected the fault was with the instrument cluster.

I managed to source a used second hand unit with exactly the same part number as the original. This is very important as over the years there have been numerous changes to the cluster (with different part numbers as a result) and you can’t program in an earlier or later cluster.

A company, who I was recommended too called AMP located in Hertford, tested all the wiring to ensure the fault was definitely in the cluster itself and then reprogrammed the replacement cluster to the car without any issues and arranged for the mileage to be corrected so that in the future there are no issues when selling the car.

Overall im very happy with the outcome and pleased that this annoying issue is now resolved.

Cost wise it was around £600 + the cost of the second hand cluster.

Hope this helps anyone suffering with the same fault.

Matt